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No. 623,547.. Patented Apr. 25, I899. G. HUMMEL.

AMPERE HOUR ELECTRIC METER.

(Application filed Dec. 31, 1897,)

4 Sheets-Sheat I.

(No Model.)

M/WM

No. 623,547. I Patented Apr. 25, 899.

a.- HUMMEL.

AMPEBE HOUR ELECTRIC METER.

(Application. filed Dec. 31, 1897.)

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L E M M U H G AMPE'BE noun ELECTRIC METER.

(Application filed Dec. 81, 1897.)

4 Sheets-Sheet 3.

(No Model.)

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Patented A r. 25, I899. a. HUMMEL.

AMPERE HOUR ELECTRIC METER.

(Application filed Dec. 81, 1897.) (No Model.) 4 Sheets-Sheet 4.

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' and top views of a circuit-reverser.

mm STATES A'raN'r price.

GEORG HUMMEL, OF MUNICH, GERMANY, ASS IGNOR TO THE ALLGEMEINE ELECTRICITATS GESELLSCHAFT, OF BERLIN, GERMANY.

AM PERE-HOUR ELECTRIC METER.

SPECIFICATION forming part'of Letters Patent No. 623,547, dated April 25, 1899.

Application filed December 31, 1897. Serial No. 665,048. (No model.)

To (all whom, it Duty concern.-

Be it known that I, GEORG HUMMEL, a subject of the King of Bavaria, residing at Mnnich,in the Kingdom of Bavaria, Germany, have invented new and useful Improvements in or Relating to Ampere-Hour Electric Meters, of which the followingis a specification.

My invention relates to electric meters especially adapted for continuous currents, and has for its object to providea meter in which the consumption of current can be read directly from the instrument, which operates under a current bearing a fixed proportion to the quantity of the current consumed; and to these ends my invention consists in an electric meter embodying the general features of construction and arrangement of parts substantially as hereinafter more particularly set forth.

In the accompanying drawings, Figure 1 is a general View showing the general arrangement of circuits and the preferred form of devices embodying the invention. Fig. 2 is a diagrammatic arrangement of the circuit. Figs. 3, 3, and S are respectively front, side, Figs. at and 5 are side and plan views of a modification. Fig. 6 is a side view of a modification of the electromagnet. Fig. 7 is an enlarged View, .partly in section, of the elastic iron rod or pin and cooperating devices. Fig. 8 is a view showing a modification of the damping devices, and Fig. 9 is aview showing a modification in the means of supporting the bell and coil.

I will first describethe general construction and arrangement of parts indicated in Fig. 1 and point out their mode of operation and will then refer to the various modifications illustrated in the drawings.

The general construction of the meter resembles somewhat in appearance the so-called DepreadArsonval galvanometer, and it comprises, essentially, a magnet, between the pole-pieces of which is located a coil traversed by a fraction of the consumption-current, and this coil is supported so as to vibrate between-the poles in accordance with the current passing through the coil and is shown as wound upon a copper bell mounted on a spindle, and proper connectionsand contact-pieces are arranged substantially as here .around this bell is wound the coil 3, the terminalsof which are connected by conductors s s with a suitable commutator u. The parts of this commutator u are connected by the conductors a a on opposite sides of the resistance w in the main circuit and-. Inside of the bell g is preferably disposed an immovable soft-iron cylinder 9, (indicated in Fig. 1,) the purpose of which is to diminish the magnetic resistance between the polepieces m, so that a strong magnetic field is obtained in which the coil 3 can move.

In order to operate the commutator a, I provide a relay comprisil'ig in the present instance the magnets r between which vibrates an armature 1", connected to one portion of the commutator. In the present instance this armature carries the sliding springs f f, and they are arranged to reverse the current through the coil 3 in accordance With their position. The relay-magnets in this instance are connected between the main working conductors and by means of a condnctort', including a resistance r, thence including the coils of the magnets 0" 1' and thence by a conductor c leading to the other line-circuit. These magnets are wound in opposition, so that the armature is not affected thereby when both magnets are energized; but in order to enable them to operate the armature r and reverse the currents in the commutator u I arrange circuits controlled by the movements of the coil 8, so that the commutator will be operated at the proper. time. Thus connected to theconductor o between the magnets 0" T is a conductor 0,

leading to a flexible arm 0, mounted on the spindle (6. Also connected to the conductor t" is a branch 0", leading to a contact arranged within the line of movement of the arm 0, and leading from the conductor c is a branch 1;, connected to a contact k also in the line of movement of the arm 0. From this arrangement it will be seen that whenever the arm 0 bears on contact 76' or 7; the magnet r or r is short-circuited, allowing the other magnet to act upon the armature 0. Connected to this armature r is a pawl r or similar device adapted to operate an indicator or counter C. \Vith this general arrange ment so far described the operation of the device as a proportional meter will be readily understood. Suppose, for instance, that the armature 0' lies near the magnet r, so that the fingers ff are in the position shown in Fig. 1. The current from the main line passes through the conductor it, fingerf, the commutator a, conductor .9 the coils, conductor 8', finger f and conductor a to the main line. Under the influence of the magnet in on the coil .9, through which the current is traveling in the determined direction, the coil is deflected and turns the hell 9 and spindle (L in a given direetionfor instance, that indicated by the arrow 011 the belland this movement continues until'the arm 0 touches the contact and then through the circuits before described the magnet 1" is short-circnited, so that magnet r attracts the armatu re 0', moving the commutator to reverse the current through the coil .9. This reversal of the current of course changes the direction of rotation of the coil, and it moves in the reverse direction until the arm 0 touches the contact 5 when the magnet r is short-circuited and the magnet r attracts the armature 1', moving the same into the position shown in Fig. 1 and again reversing the circuit through the coil .9 and at the same 1ime making the proper indication on the register or counter C. It willbe seen thatthese movements will continue as long as the proper current is flowing and that the coil 8 will move in one or the other direction,according as the current is flowing therethrough, and will continue to move until through the medium of the arm 0 and contacts 7.1 76 the relay is operated to effect the reversal of the current through the coil.

The construction and arrangement are operative to perform a direct indication proportional to the current consumed, assuming that friction and other forces or resistances are ignored. Itis,however, desirable to provide means for overcoming or neutralizing these disturbing causes, so that under all conditions the indication shall represent a true proportion al amou nt of current used, and I therefore provide additional means for accomplishing this object, which I will now describe.

It will be understood that as the coil or an mature .9 moves under the influence as above described it acquires a certain velocity, and when it is about to reverse its movement it is desirable to provide some means for overcoming its momentum and inertia. These are overcome to a greater or less extent by means of the arm 0 striking against the contact-pieces 70 73, respectively; but this would cause an undesirable wear and tear of the contacts, especially in cases where there is a high consumption of current. To further aid in accomplishing this result, I provide the spindle a with a long elastic iron rod or pin t, which is arranged to come in contact with stops t, as best shown in Fig. 7, and in this way the oscillation of the armature or coil .9 beyond its proper position is prevented. 'lhe elasticity of the pin 15 takes up the energy accumulated in the masses of the bell, spindle, and coil and in turn reacts to impart thereto an impulse on the return oscillation or vibration, and in this way the momentum of the armature s is not only overcome, but is taken up and rendered valuable in overcoming the inertia of the armature in starting it in its oppc 'te excursion.

In order that the number of oscillations of the armature .9 may actually be proportional to the consumption-current, the work performed by the coil 3 under the influence of the magnet must be eliminated, and in the present instance this work is practically consumed by a damping device in the form of the metallic bell g, already mentionedgvhich moves with the coil in the magnetic field.

lly neglecting the losses due to friction in the bearings the following equation may be made: A I D, wherein A represents the work performed by the motor and l) the work consumedbythedampingdevice. Nowthework performed by the armature or coil 5' is proportional to the intensity I of the current flowing through the coil and, on the other hand, the work of (lamping is proportional to the number of oscillations of the armature. Hence:

A:c,.I; D 0

in which 0 and 6 are proportional factors, which are determined with relation to the instrument itself.

From the above follows the fundamental equation:

I c I;

that is, the number of oscillations of the armature is proportional to the intensity of the current flowing through the coil s, if one neglect the different losses.

In order that the results given by the electric meter or counter may be always proportional to the actual intensity of the current, the current flowing through the coil s must be a determined fraction of the consumptioneurrent flowing through the main circuit. Therefore the ratio between the resistance 10 and the resistance inserted in the circuit parallel to the same, which is composed of the coils and conductors leading thereto, must remain entirely constant; but the absolute values of these resistances become altered by the raising of the temperature of the parts, and the relation of the one to the other can lCO ICS

of the copper damping-bell g diminishes as the temperature rises, the whirling currents become weaker in the same proportion, and in accordance therewith the damping action gets smaller, so that although the intensity of the current remains unaltered in the coil .9 the armature oscillates too quickly, so that the results given by the apparatus are not ab solutely correct. Care must be taken, therefore, that under comparatively high temperatures a somewhat smaller fraction of'the main current goes through the coil 8, so that a feebler damping action corresponds to a weaker impulse,and the proper number of oscillations is produced. This may be accomplished in the following way: The resistance 10, through which the greatest part of the consumptioncurrent flows, is made of a material possessing a low coefficient of temperature. Thus the resistance of said material only changes slightly under a rising temperature, and this, for example, is the case when nickel alloys, such as nickeline or equivalent materials, are used, while the coil .9 possesses a high coefficient of temperature, being made, for instance, of copper, so that its resistance in case of the temperature rising increases more rapidly than the resistance of 10. From this it follows that when the temperature rises a comparatively smaller fraction of the consumption-current goes through the coils, and by suitably choosing the relations of the constituents to each other the instrument is made insensitive to wide changes in temperature.

Besides the energy consumed by the damping the mechanical resistances in the axlebearings and in the tension of the conductingwires of the coil must be overcome. Further, it is necessary that the arm 0 be pressed with sufficient force against the contacts 75 k to avoid resistance due to poor electric contact. These resistances become of more importance as the proportional current is small and interfere with the absolute and correct indication of the amount of the consumption-current used. Further, the pull exerted by the constant magnetic field on the coil 8 does not at all times remain the same during the whole movements or oscillations of the armature, but varies with the sine of the angle of deflection. Thus, for instance, if the deflectionpath extends one hundred and eighty degrees the active force at both the end positions must necessarily be zero, so that in case of a small consumption-current the oscillations of the armature would not occur with the desired certainty. In order to avoid this and at the same time for the sake of eliminating the influence of the noxious resistances to motion, so that the counter will indicate even the smallest consumption of current, an auxiliary armature or keeper is provided, which in the present instance is keyed upon the spindle a, which auxiliary armature is subjected to the action of a constant magnetic field and arranged in such away that the maximum development of force takes place at or about the end of the deflection or path of oscillationthat is, immediately before the arm 0 hits the contacts 70 respectively. In Fig. 1 this auxiliary armature is shown as a softiron rod h, which is disposed vertically with regard to the winding-plane of the coils. The constant magnetic field is produced in this case by two polar extensions p p of the poles m.

It will readily be understood that a constant or permanent magnet completely independent of the magnet 'm can be used instead of the polar extensions 1) p, and such a one is indicated in Figs. 4 and. 5, in which M may be a permanent magnet or it may be a softiron magnet provided with coils M which coils will of course be arranged in a shuntcircuit. So, too, the effect of the auxiliary armature It can be augmented by substituting for the simple iron rod h a rod-shaped electromagnet h, as indicated in Figs. 4 and 5, the winding of which is of course disposed in a shunt-circuit, so that the intensity of the current to be induced can be altered at will and so that after each oscillation its poles can be reversed, and this can be accomplished by the commutator shown in Fig. 1 or in any other similar and well-known way. I

Instead of the permanent magnet m, as shown in Fig. 1, an electromagnet M as indicated in Fig. 6, can be used, the coils M thereof being'connected in a sh tint-circuit, so that the intensity of the field will be constant as long as the working tension remains the same, which is generally the case. In case the damping action due to the bell g is insufficient to neutralize or annihilate the work performed by the coil 3, the damping action canbe reinforced by means of a plate or disk D, mounted on the spindle a, said disk being arranged to oscillate in a constant magnetic field D, as indicated in Fig. 8.

Instead of a flat commutator, as shown in Fig. 1, any other ordinary form of commutator may be used, one well-known form of the round type being indicated in Figs. 3, 3, and 3 the operation of which is well understood by those skilled in the art and need not be recited, it being of course connected to be operated by the relay-armatu re 7" or other equivalent Way.

In the form of apparatus represented in Fig. 1 the spindle a of the oscillating armature is shown as carried in the usual way in a stepped bearing; but it is impossible to obtain a perfectly regular lubrication of the bearin gs, and the friction therefrom varies at short intervals, so that the accuracy of the results given by the apparatus is impaired.

Fig. 0 such a construction is indicated, in which the torsional force required is reduced to a minimum. Thus the spindle a is bored through its whole length and is supported by the wires a, which extend through the whole bore and are connected to the lower part of the spindle by a suitable cross-piece a and the supporting wire or wires are protected. The spindle may be guided in the bearings a" c.

Having thus described the essential features of my invention, together with the refinements whereby extreme accuracy may be obtained, and without limiting myself to the precise details of construction shown and described, what I claim is 1. In a registering electric meter for continuous currents, the combination with a magnet having a constant field, of a coil arranged in said constant field, means for supporting the coil to permit its oscillation therein, a.

damping-bell also arranged in the field, a commutator controlling the circuits through said coil, and means controlled by said coil for controlling the commutator, substantially as described.

2-. In a registering electric meter for conti nuous currents, the combination with a magnet having a constant field, of a coil arranged in said constant field, means for supporting the coil' to permit its oscillation therein, a damping device also arranged in the field, a commutator controlling the circuits through said coil, connections controlled by the movements of the coil for controlling the com mntator, an auxiliary armature connected to the coil,and a constant magnetic field for said auxiliary armature, substantially as described.

3. In a registering electric meter for continuous currents, the combination with a magnet having a constant magnetic field, of a coil arranged in said magnetic field, a spindle supporting the coil, a commutator controlling the circuits through said coil, an arm mounted on the spindle, contacts arranged within the path of oscillation of the arm, and a relay controlled by said contacts and controlling the commutator, substantially as described.

4. In a registering electric meter for continuous currents, the combination with a magnet having a constant magnetic field, of a coil arranged to oscillate in said field, a spindle supporting said coil, a contact-arm mounted 011 said spindle, contacts arranged within the path of oscillation of said arm, an elastic pin mounted on the spindle, stops arranged Within its path of oscillation, and circuits and connections whereby the current through the coil is automatically reversed, substantially as described.

5. In a registering electric meter for continuous currents, the combination with a magnet having a constant magnetic field, of a coil arranged to oscillate in said field, a spindle supporting said coil, a contact-arm carried by said spindle, contacts arranged within its path of oscillation, an elastic pin mounted on the spindle, stops arranged within the path of oscillation of said pin, an auxiliary armature also mounted on the spindle, a constant magnetic field for said auxiliary armature, and circuits and connections whereby the current through the coil is automatically controlled, substantially as described.

(5. In a registering electric meter for contin uous currents, the combination with a magnet having a constant magnetic field, of 'a spindle,a damping device carried by the spindle, a coil mounted on the damping device, a contact-arm carried by the spindle, contacts arranged to be operated by the arm, an elastic pin carried by the spindle, stops therefor, an auxiliary armature carried by the spindle, polar extensions creating a constant magnetic field for said auxiliary armature, and circuits and connections for automatically reversing the current through said coil, substantiall y as described.

7. In a registering electric meter for continuous currents, a magnet havinga constant field, a coil supported in said field, a hollow spindle supporting the coil, wires extending through said spindle and supporting the same, and means for guiding the spindle, substan tially as described.

8. In a registering electric meter for continuous currents, a magnet having a constant magnetic field, a coil oscillating in said field, a main circuit including a resistance, and electric connections between the main circuit and coil, the coil being of such material that the coefficient of temperature with relation to electricresistance is greater than the coefficient of temperature of the resistance in the main circuit, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORG IIUMMEL.

Vitnesses:

ERNsT GLAS, EMIL IIENTZEL. 

